In the field of shoulder prostheses it is known, for example from U.S. Publication No. 2005/0049709 (based on FR-A-2 859 099), to use a glenoid component that includes a base capable of resting against the patient's glenoid cavity. The base is combined with a fixing member intended to penetrate deeply into this glenoid cavity in order to connect it securely to the aforementioned component.
U.S. Publication No. 2005/0049709 teaches a fixing member is in the form of a keel that includes a main longitudinal axis. The base has a concave surface opposite the keel that is capable of cooperating with a totally hemispherical head of a humeral component of the shoulder prosthesis. For satisfactory implantation, from the anatomical point of view, of the glenoid component in the glenoid cavity the keel of this component has a length which is less than that of the base resting against the glenoid cavity. In addition, the keel is slightly tapered so that the length of its free end is less than the length of this keel in the region of its zone of connection to the base.
U.S. Publication No. 2005/0261775 also discloses an alternative solution in which the aforementioned fixing member is formed by a solid stud. As in the case of the aforementioned keel, this stud has dimensions that are less than these in the region of its zone of connection to the base, for anatomical reasons. A stud of this type is relatively invasive toward the patient. Its use necessitates the removal of a significant portion of the patient's bone stock, which is detrimental in particular when refitting the implant.
U.S. Pat. No. 3,869,730 discloses a shoulder prosthesis comprising a glenoid component that is equipped with a first diametral plate as well as two half plates extending transversely to this main plate. However, these various plates for fixing the component in the glenoid cavity are not anatomical since their dimensions are identical to those of the base and, consequently, they are capable of leading to at least partial destruction of the glenoid cavity. In this respect, it will be noted that these plates cannot be considered as a fixing keel, as mentioned above.
Bicknell et al., Does Keel Size, The Use Of Screw, And The Use Of Bone Cement Affect Fixation of A Metal Glenoid Implant?, 12 J of Shoulder Elbow Surg. 268 (2003) discloses a symmetrical blade-type, cross-keeled glenoid components. The five cross-keeled glenoid components tested varied only in size, not in the configuration had keel. The article concludes that the size of the keel was not found to have a significant effect on the stability of the glenoid components, as measured by the variable of contra-lateral lift-off. The article also concludes that supplemental screw fixation significantly improved implant fixation relative to the un-cemented keel, regardless of keel size. The keel was not optimized to the patient's anatomy.